This week at Mawson: 22 November 2019

The Summer ARPANSA team report from Mawson.

ARPANSA at Mawson

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) is the Australian Government’s primary authority on radiation protection and nuclear safety. We aim to protect the Australian people and the environment from the harmful effects of radiation.

A Comprehensive Nuclear-Test-Ban Treaty (CTBT) to ban all nuclear explosion tests was created in 1996. To date 184 countries have signed the CTBT and of these 168 have ratified. Australia has both signed and ratified the CTBT.

An International Monitoring System (IMS) consisting of 337 stations is being constructed to monitor compliance with the Treaty. These monitoring facilities use a variety of methods to detect evidence of nuclear testing. Seismic, hydroacoustic and infrasound stations are employed to monitor the underground, underwater and atmosphere environments, respectively while radionuclide stations detect radiation from atmospheric sampling.

ARPANSA is responsible for carrying out Australia's radionuclide monitoring obligations to the Comprehensive Nuclear-Test-Ban Treaty. This entails the installation, implementation and operation of seven IMS stations within Australia and its Territories. In addition, ARPANSA has recently taken over responsibility for the radionuclide stations in Fiji and Kirbati. In November 2019 Sandra Sdraulig and Stuart Henderson from ARPANSA arrived at Mawson to carry out maintenance tasks at the CTBT station.

The radionuclide monitoring process involves collecting particulate matter from the air onto a piece of filter material on a high volume air sampler for 24 hours. After this time the filter is taken from the air sampler, compressed into a disk. The disc is then placed in a chamber to allow natural radionuclides to decay for another 24 hours. Finally, the filter sample is placed on a gamma detector for a further 24 hours to be analysed. A computer monitors the workflow, keeping track of every sample as it progresses through the system and collects the data that could provide evidence of nuclear testing. The data relating to the sampling conditions and radionuclides measured is then forwarded by satellite to the International Data Centre in Vienna where it is compiled and released to countries participating in the Treaty.

This process occurs every day of the year. A new filter must be loaded each day and the previous days’ samples moved through the analysis stages. Once analysed, samples are catalogued and archived to eventually be returned to ARPANSA and on to the IDC in Vienna. ARPANSA relies on assistance from AAD staff to ensure that the daily tasks are completed. This year it has been Comms Officer Dave and Station Leader Kyle who have kept the station running. Thanks guys!

Thanks to all the Winterers at Mawson for making us feel welcome on Station and for helping us to complete our work. Also a special thanks to Chris 'Scottish' George for taking us on a field tour of Henderson and Rumdoodle Huts. 

- Stuart & Sandra (Mawson Summer ARPANSA Team) 

Sandra Sdraulig operating the press to compact the filter sample to a disc for analysis.
Sandra Sdraulig operating the press to compact the filter sample to a…
(Photo: S. Henderson)
Sandra Sdraulig closing the detector shield after inserting the sample disc on top of the detector.
Sandra Sdraulig closing the detector shield after inserting the sample disc on…
(Photo: S. Henderson)
Sandra Sdraulig and Blue Hagglunds in Mawson's Framnes Mountains.
Sandra Sdraulig and Blue Hagglunds in Mawson's Framnes Mountains.
(Photo: S. Henderson)
Stuart Henderson visiting his namesake peak - Mount Henderson in Mawson's Framnes Mountains.
Stuart Henderson visiting his namesake peak - Mount Henderson in Mawson's Framnes…
(Photo: S. Sdraulig)